assuming this is supposed to mean six months, how did you update it? Did you use someone else’s account to download the update?
What is the model year and specs of your mac? Starting with Mac-OS Sierra there were limitations on who could upgrade , but those were removed when they revised the distribution. However with High Sierra the limitations are back and although it is possible to "trick" the installer into putting High Sierra on a Mac that doesn't meet the specs my roommate who did that said his Mac went from running well, to working at a crawl and beach-balling left and right. It's just because High Sierra leverages the hardware that was part of the requirements for the install and when it doesn't find the hardware it going on a quest trying to find it, and it's very persistent. Eventually the process crashes (but this now creates a vulnerability in your system as a lot of the processes are security and maintenance based.) so if your hardware doesn't have the required components you may be able to install it and win the battle, but in the end you will lose the war because your system is open to being corrupted.
